OBJECTIVE To evaluate the effects of using CO(2) as negative contrast agent in decreasing the overlapping on the pancreaticobiliary system from intestinal fluids. METHODS We evaluated the magnetic resonance cholangiopancreatography (MRCP) images in 117 patients divided into two groups (group 1, without taking gas producing crystals to produce CO(2), n = 64; group 2, with CO(2), n = 53) in a 1.5T unit using MRCP sequence. Anatomic locations of intestinal fluids distribution, overlapping with common bile duct (CBD) and pancreatic duct (PD), were evaluated. RESULTS In the group with CO(2), the decrease in distribution of intestinal fluids was significant in the gastric antrum (P = 0.001) and duodenal bulb (P < 0.001), but not in the gastric fundus and body and in the second portion of the duodenum (P = 1.000, P = 0.171, and P = 0.584 respectively). In the group with CO(2), the decrease in overlapping with CBD was significant (P < 0.001), but the decrease in overlapping with PD was not (P = 0.106). CONCLUSIONS MRCP with carbon dioxide as negative contrast agent would decrease intestinal fluids in the gastric antrum and duodenal bulb, thereby decreasing overlapping with the CBD.